Only those who are gullible take every advertisement seriously.
A
fallible
B
enthusiastic
C
unsuspecting
D
unrealistic
Correct Answer: unsuspecting
fallible : capable of making mistakes or being wrong.enthusiastic : having or showing intense and eager enjoyment, interest, or approval.
unsuspecting : (of a person or animal) not aware of the presence of danger; feeling no suspicion.
unrealistic : not realistic.
gullible : easily persuaded to believe something; credulous.
Synonym of gullible is unsuspecting